Detachable latched electrical plug and socket connection



March 25, 1952 TRIPLETT 2,590,354

DETACHABLE LATCHED ELECTRICAL PLUG AND SOCKET CONNECTION Filed Sept. 27,1950 s Sheets-Sheet 1 FIG. I 3 1 28 24 y N i 27 LEE TRIP LETT INVENTORATTORNEY S March 25, 1952 TRlPLETT 2,590,354

DETACHABLE LATCHED ELECTRICAL PLUG AND SOCKET CONNECTION Filed Sept. 27,1950 5 Sheets-Sheet 3 FIG. 7

FIG. 8

LEE TRlPLETT, INVENTOR BYMI 15,, W

1 ATTORNEYS Patented Mar. 25, 1952 DETACHABLE LATCHED ELECTRICAL PLUGAND SOCKET CONNECTION Lee Triplett, Magna, Utah, assignor of one-thirdto James L. Jones and one-third to Richard A. Sweet, both of Salt LakeCity, Utah Application September 27, 1950, Serial No. 187,079

The invention of which the following is a detailed specification relatesto a quick detachable latched electrical connection suitable for a wallor utility outlet. It comprises a fixed structure mountedin 'a wall boxand providing suitable sockets which cooperate with the prongs ofattaching plugs.

In the usual practice of supplying electric current from fixed outletsto portable electrical attachments, any tension or slight pull on" theelectric cord is apt to break the electrical connection, or evendis-connect the plug from the outlet fixture itself. Thus, in the use ofordinary domestic appliances, such as electric pressing irons, electriccooking utensils and the like, interruption of the current may be causedWithout the operator being aware of the fact until later. This resultsin much lost time.

Again, it is frequently the case that such an inadvertent interruptionof the current will be of material damage where articles are beingoperated on by electrical attachments and continuous electric supply isessential to uniform work on product. Thus, an accidental interruptionof current may cause irregular effects in paint spraying, electricwelding, soldering, grinding, polishin and sanding.

An object of my'invention is to provide asimple but effective latchagainst inadvertent detachmentof the electrical connectors dueto normaldirect pull on the electric cord. At the same time, theinvention willpermit an emergency separation' by a stronger pull.

A further object of my invention isto provide spring means by which theconnecting plug will beheld in firm, latched position. I

Astill further object of my invention is to permit ready detachment ofthe electrical connection by a. small tilting movement of the plugrelative to the outlet fixture.

,Amongthe objects of my invention is to improve the typeof contactbetween the fixture and the prongs of the plug.

It is also a further object of my invention to keep the prongs of-theplug in separate compartments, thus avoiding the possibility of short-.circuiting.

Among the objects of'my invention is also provision-to compensate forordinary wear on the plugs or weakened spring contact of thecurrentcarrying spring fingers. Theinvention has'been illustrated forthe purpose of example in the accompanyin drawings in which I haveillustrated the preferred form and where:

Claims. (01. 173-330) Fig. 1 is a front view of the utility outletfixture showing the improved socket members;

Fig. 2 is a front view of the fixture with the cover removed;

Fig. 3 is a side elevation of the fixture partly in section taken alongthe line of line 3-3 of Fig. 1, showing the connecting plugs inserted;

Fig. 4 is a vertical section of the upper unit taken on the line 6-4 ofFig. 2.

Fig. 5 is a front view of the center plate;

Fig. 6 is a side elevation of the same;

Fig. '7 is a side elevation of the supporting bar;

Fig. 8 is a, side elevation of the socket member;

Fig.9 is a vertical section on the line 99 of Fig. 2; and

Fig-10 is-a side elevation of the plug.

In brief, the invention comprises an improved socket member incombination with a plug which has been modified to cooperate effectivelywith the improved socket. The socket is maintained in a tiltable floatinposition by being pivoted to the frame members. Each socket member isbifurcated to provide spaced parallel compartments extending rearwardly.Each compartment contains one resilient spring finger which carries thecurrent.

Each compartment is traversed by a springheld latch bar or detent towhich the prong becomes fastened in normal operation.

The'plug is inserted in the face of the socket member, and one prongpasses rearwardly through each compartment. In the operation ofinsertion, the end of the prong contacts the latch, and this causes theplug and socket to be tilted in order that the prongs may pass the latchbar.

This tilting movement may be anticipated by the operator, thusfacilitating engagement of the parts.

As soon as the latch bar has dropped into the locking notches of theprongs, a holding spring operates to restore the socket and plug intothe normal position in the plane of the cover.

As illustrated in the accompanying drawings, the preferred form of myinvention consists in a novelsocket and plug arranged to be mounted inthe present-day wall box H. Thesewall boxes are-familiar and include acover plate I2. This cover plate is attached by means of a fasteningscrew I3.

The remaining visible portions are one or more socket members l4 intowhich the plugs l5 are inserted.

The wall box ll carries alon its longitudinal axisa mounting strap l6.This strap has tongues I! :by which it is bolted to theinwardly'extending flange or tongues'of the wall box.

The strap I9 is of metal which has been bent into a special form but inordinary use has the rigid form illustrated in Fig. '7. Inwardly of eachtongue I! the strap I6 is bent backwardly and ends in a bight i8. Thesebights serve to grip locking pins l9, l9 tightly and hold them inposition. Inwardly of the bights l8, IS the strap |6 carries outwardlyprojecting resilient springs 26, 20. These springs are used to maintainthe socket members in the plane of the cover plate l2.

The locking pins l9, l9 extend beyond the sides of the strap I6 in themanner shown in Fig. 2. The pins |9, |9 are of wood, composition, orother suitable electrically insulating material.

The strap H at its mid-point is enlarged to form a circular portion 22.This portion has peripheral tongues 23.

A bridge 24 made of plastic or other insulating material is formed witha series of slots 25. These slots are spaced to conform to the tongues23. The tongues 23 are passed through the slots 25 and bent over so thatthe bridge 24 is rigidly mounted on the strap I6.

A nut 26 is firmly held centrally of the bridge 24. This nut receivesscrew I3 which holds the cover plate in position.

The bridge 24 on its outer side flanges 2'1, has a plurality of grooves28.

The bridge 24 serves as a mounting for a pair of terminal bars 29. Theseare of conducting metal and are mounted on the sides of the bridge 24 bymeans of screws 30. Lugs 3| project inwardly from the bars 29 and areheld within the grooves 28, 28. The screws 3|] form binding posts bywhich wires are fastened to connect the bars 29 to opposite sides of anelectric circuit.

A rivet 32 passing through each end of the bars 29, forms a pivot forholding a socket member |4, |4.

Each socket member consists of plastic or similar insulating materialhaving an enlarged slotted head 33. This head consists of two rearwardlyextending sockets 34, 34. These sockets are reinforced at the corners byribs 35, 35.

Each socket 34 is separated from the companion socket by a spaceslightly in excess of the width of the strap Hi.

The sockets 34, 34 are slotted as at 36 to provide clearance to receivethe lock pins I9. The slots 36 extend to substantially the center oraxis of the sockets 34, as shown in Fig. 4.

The front portion 33 of the socket member rests against spring 29 sothat the socket member normally lies in the plane of the cover plate, asshown in full lines in Fig. 4. However, the rivets 32 form pivots aroundwhich the sockets may tilt into the inclined positions shown in dottedlines in Figs. 3 and 4. This is accomplished by pressure upon thesprings 20.

As the socket members tilt around the rivets 32, the lock pins l9, l9ride up in the slots 36 away from the center of the socket members 34.

Each socket member 34 is slotted at one end to permit the terminal bars29 to fit within the sockets as indicated in Fig. 2. Within the socketmembers and on the inner faces of the bars 29, a resilient metalliccontact piece 31 is held by the rivets 32. This contact member 31 is inthe form of a letter J. A tongue 43, struck up from the long side andsent across forms a contact (see Fig. 2). The rivet 32 forms a firmfastening between the fiexible contact 31 and the adjacent terminal bar29, as well as providing the pivot around which the socket member mayoscillate.

The plug |5 has a body 38 of the usual form and terminal connections ofthe usual type to the 2-wire electric cord 39. Each plug has a pair ofindependent prongs 40, 40. The prongs are spaced parallel and go intothe slots provided in the socket members l4.

Each prong is notched, as shown at 4|, on opposite sides to provide anopening large enough to receive a lock pin IS. The prong 4| has slidingcontact with the short arm of the contact 31, as shown in Fig. 2.

A desirable feature is the provision of an open slot 42 in the prongbetween the notches 4|, 4| (see Fig. 10).

In the event that continued use enlarges the notches 4|, 4|, they may bespread apart to increase the frictional engagement with the pin I9. Bynotching opposite sides of each prong, the plug is reversible inposition.

The plug is inserted in the slots of the socket member until the prongsstrike the pin IS. The curved end of the prongs deflect the latter andthis movement may be assisted by manually tilting the plug and thesocket member into the position shown in dotted lines in Figs. 3 and 4.

This permits the prongs to ride over the lock pin l9. The lock pin thenfalls into the notch 4| of the prong and the spring 20 restores thesocket member and the plug to the full line position shown in Fig. 3.

This attachment of the plug is reasonably secure against inadvertentdislodgement. The locking pin holds the prongs of the plug againstnormal pull in the perpendicular direction. The

' stress is transmitted directly to the wallbox cal through the strapl6.

Detachment of the plug is easily accomplished by tilting the socketmember around the pivot 32. This compresses the spring 20. It alsolowers the prongs of the plug to a position where they are no longerheld by the locking pin. Hence they may be drawn out freely.

The above described arrangement provides a simple, durable and effectivemeans for effecting the connection of electrical devices to the con- 2ventional circuit outlets. It is adaptable for present-day equipment. Itis easily operated but at the same time not subject to inadvertentdetachment.

While the preferred form of the invention has been illustrated. anddescribed, many changes in minor details of construction, proportionsand materials may be made without departing from the scope of theinvention as defined by the following claims.

What I claim is:

1. In combination, a fixed wall box, a median strap mounted thereon, acenter plate on the strap, a pair of parallel contact bars held by thecenter plate, a socket member tiltably pivoted on the adjacent ends ofthe contact bars, said socket member being transversely slotted, alocking bar on the strap for projection into the socket member, and aplug having a pair of notched prongs insertable in the socket member andin looking engagement with the locking bar.

2. In combination, a fixed wall box, a median strap mounted thereon, acenter plate on the 3. In combination, a fixed wall box, a median strapmounted thereon, a center plate on the strap, a pair of parallel contactbars held by the center plate, a socket member tiltably pivoted on eachpair of adjacent ends of the contact bars, said socket member beingtransversely slotted,

" locking bars on the strap for projection into each socket member,spring contacts attached to each contact bar within the socket members,said spring contacts having opposed portions, and plugs having pairs ofnotched prongs insertable between said portions of the spring contactsand engaging the said locking bars.

4. In combination, a fixed wall box, a median strap mounted thereon, acenter plate on the strap, a pair of parallel contact bars centrallyanchored to the center plate, a socket member tiltably pivoted on eachpair of adjacent ends of the contact bars with the said endstransversely disposed within the outer walls of the socket members,resilient contact members within the socket members, pivots passingthrough the contact members, the ends of the contact bars and the outerwalls of the socket members, and plugs having pairs of notched prongsinsertable between and engaging said contact members, said socketmembers having transverse slots on their inner walls and a locking barmounted on the median strap for reception through said transverse slotsand engagement with said notched prongs. a

5. In combination with a wall box, a median strap having ends forattachment to the box, intermediate bights, transverse locking bars heldin the bights and springs opposite the locking bars.

LEE TRIPLETT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,281,739 Wright May 5, 19422,447,597 Reed Aug. 24, 1948 2,473,570 Chirelstein June 21, 1949 FOREIGNPATENTS Number Country Date 177,713 England Apr. 6, 1922

